The Tcpdump Group git mirrors - tcpdump/blob - print-openflow.c

   1 /*
   2  * This module implements printing of the very basic (version-independent)
   3  * OpenFlow header and iteration over OpenFlow messages. It is intended for
   4  * dispatching of version-specific OpenFlow message decoding.
   5  *
   6  *
   7  * Copyright (c) 2013 The TCPDUMP project
   8  * All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  20  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  21  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  22  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  23  * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  24  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  25  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  26  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  27  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  29  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  30  * POSSIBILITY OF SUCH DAMAGE.
  31  */
  32
  33 /* \summary: version-independent OpenFlow printer */
  34
  35 #ifdef HAVE_CONFIG_H
  36 #include <config.h>
  37 #endif
  38
  39 #include "netdissect-stdinc.h"
  40
  41 #include "netdissect.h"
  42 #include "extract.h"
  43 #include "openflow.h"
  44 #include "oui.h"
  45
  46
  47 #define OF_VER_1_0    0x01
  48
  49 const struct tok onf_exp_str[] = {
  50         { ONF_EXP_ONF,               "ONF Extensions"                                  },
  51         { ONF_EXP_BUTE,              "Budapest University of Technology and Economics" },
  52         { ONF_EXP_NOVIFLOW,          "NoviFlow"                                        },
  53         { ONF_EXP_L3,                "L3+ Extensions, Vendor Neutral"                  },
  54         { ONF_EXP_L4L7,              "L4-L7 Extensions"                                },
  55         { ONF_EXP_WMOB,              "Wireless and Mobility Extensions"                },
  56         { ONF_EXP_FABS,              "Forwarding Abstractions Extensions"              },
  57         { ONF_EXP_OTRANS,            "Optical Transport Extensions"                    },
  58         { 0, NULL }
  59 };
  60
  61 const char *
  62 of_vendor_name(const uint32_t vendor)
  63 {
  64         const struct tok *table = (vendor & 0xff000000) == 0 ? oui_values : onf_exp_str;
  65         return tok2str(table, "unknown", vendor);
  66 }
  67
  68 static void
  69 of_header_print(netdissect_options *ndo, const uint8_t version, const uint8_t type,
  70                       const uint16_t length, const uint32_t xid)
  71 {
  72         ND_PRINT("\n\tversion unknown (0x%02x), type 0x%02x, length %u, xid 0x%08x",
  73                version, type, length, xid);
  74 }
  75
  76 /* Print a TCP segment worth of OpenFlow messages presuming the segment begins
  77  * on a message boundary. */
  78 void
  79 openflow_print(netdissect_options *ndo, const u_char *cp, u_int len)
  80 {
  81         ndo->ndo_protocol = "openflow";
  82         ND_PRINT(": OpenFlow");
  83         while (len) {
  84                 /* Print a single OpenFlow message. */
  85                 uint8_t version, type;
  86                 uint16_t length;
  87                 uint32_t xid;
  88
  89                 if (len < OF_HEADER_FIXLEN)
  90                         goto invalid;
  91                 /* version */
  92                 version = GET_U_1(cp);
  93                 OF_FWD(1);
  94                 /* type */
  95                 type = GET_U_1(cp);
  96                 OF_FWD(1);
  97                 /* length */
  98                 length = GET_BE_U_2(cp);
  99                 OF_FWD(2);
 100                 /* xid */
 101                 xid = GET_BE_U_4(cp);
 102                 OF_FWD(4);
 103                 /*
 104                  * When a TCP packet can contain several protocol messages,
 105                  * and at the same time a protocol message can span several
 106                  * TCP packets, decoding an incomplete message at the end of
 107                  * a TCP packet requires attention to detail in this loop.
 108                  *
 109                  * Message length includes the header length and a message
 110                  * always includes the basic header. A message length underrun
 111                  * fails decoding of the rest of the current packet. At the
 112                  * same time, try decoding as much of the current message as
 113                  * possible even when it does not end within the current TCP
 114                  * segment.
 115                  *
 116                  * Specifically, to try to process the message body in this
 117                  * iteration do NOT require the header "length" to be small
 118                  * enough for the full declared OpenFlow message to fit into
 119                  * the remainder of the declared TCP segment, same as the full
 120                  * declared TCP segment is not required to fit into the
 121                  * captured packet buffer.
 122                  *
 123                  * But DO require the same at the end of this iteration to
 124                  * decrement "len" and to proceed to the next iteration.
 125                  * (Ideally the declared TCP payload end will be at or after
 126                  * the captured packet buffer end, but stay safe even when
 127                  * that's somehow not the case.)
 128                  */
 129                 if (length < OF_HEADER_FIXLEN) {
 130                         of_header_print(ndo, version, type, length, xid);
 131                         goto invalid;
 132                 }
 133                 /*
 134                  * Decode known protocol versions further without printing the
 135                  * header (the type decoding is version-specific).
 136                  */
 137                 switch (version) {
 138                 case OF_VER_1_0:
 139                         of10_header_body_print(ndo, cp, type,
 140                                                length - OF_HEADER_FIXLEN, xid);
 141                         break;
 142                 default:
 143                         of_header_print(ndo, version, type, length, xid);
 144                         ND_TCHECK_LEN(cp, length - OF_HEADER_FIXLEN);
 145                 }
 146                 if (length - OF_HEADER_FIXLEN > len)
 147                         break;
 148                 OF_FWD(length - OF_HEADER_FIXLEN);
 149         } /* while (len) */
 150         return;
 151
 152 invalid: /* fail the current packet */
 153         nd_print_invalid(ndo);
 154         ND_TCHECK_LEN(cp, len);
 155         return;
 156 trunc:
 157         nd_trunc(ndo);
 158 }